During 2015 the Austrian cement manufacturer Schretter & Cie GmbH & Co KG modernised its grinding process. The former system with a high pressure grinding roll (HPGR) working in a pre-grinding mode was upgraded to a grinding circuit with an HPGR in semi-finish grinding mode. A compact 2-Stage Koesep air classifier, the latest development of Köppern, based in Germany, was installed. The new combined air classifier was implemented during ongoing operation with total plant downtime of just 40hr. One year after re-commissioning of the grinding system it can be noted that the modernisation improved production, stabilised the process and reduced energy consumption. This article reflects experiences made throughout the first year of operation and shows effects with regard to production and energy consumption.

Written by Interview by Peter Edwards & David Perilli, Global Cement Magazine

09 November 2016

The Cemex South Ferriby plant has stood proudly on the Humber Estuary in North Lincolnshire, UK for nearly 80 years. Over the years, the river has been a vital lifeline for the plant to bring in raw materials and export cement. However, in December 2013 the plant was completely overwhelmed by a tidal surge, leaving it with major damage. Here, key plant staff describe the damage, the renovation and the plant’s unusual semi-dry Lepol grate production process.

The burning zone of a rotary lime kiln has the highest process and shell temperatures of anywhere in the kiln. Increasing production by increasing burning temperatures necessitates the selection of higher quality basic wear lining brick (improved thermochemical resistance) to optimise the refractory campaign life. Such bricks also have higher conductivity and, with minimal coating formation, shell temperatures are further increased. The resulting high shell temperature can cause shell deformation, increased energy consumption, loosening of the refractory lining and rotational and migration issues. Until now, dedicated insulation linings have not been used in such intensely thermomechanically stressful applications due to their inherent softness and fragility. Rotary kiln lime producers have to tolerate unacceptably high shell temperatures and energy consumption in order to achieve increased production targets. To correct this, a 13mm thick structural insulation board manufactured by Pyrotek, with world’s best thermomechanical properties, was trialed in order to reduce the shell temperatures. Its performance was assessed over a three year campaign.

The use of Supplementary Cementitious Materials (SCMs), such as slags and fly ash, in cement blends is a well-established methodology for reducing clinker factor while imparting beneficial properties to the eventual concrete product. Here Global Cement speaks to Charlie Zeynel of ZAG International Pty. Ltd., a company that sources, markets and sells a full range of minerals and raw materials as well as intermediate and finished products to a wide range of industries. What are the current trends and what can we expect from the SCM markets in the future?

Global seaborne cement and clinker trading volumes are relatively small compared to global production levels but they are strategically important and have a significant impact on the profitability of the companies involved. Here, Ad Ligthart from Cement Distribution Consultants presents the latest cement and clinker trade patterns, with a focus on Chinese over-capacity and rapidly-developing import markets in Africa and the US.